Republican politicians appeared to be sudden converts for immigration reform after so many Hispanics voted against them in the November elections.

But in the House on Tuesday, conservatives were wary of moving too fast or too far.

Still, panelists told the lawmakers a broken system is chasing away the very people who could help turn American's economy from bust to boom.

"It rips families apart at the seams to be in this kind of limbo. And it injures communities because we're not able to fully take advantage of the brainpower of those young people," San Antonio Mayor Julian Castro said.

"I believe that brainpower is the currency of success in this 21st century economy," Castro said.

"An estimated 40 percent of scientists in the U.S. are immigrants and studies show immigrants are twice as likely to start businesses," Vivek Wadhwa, author of The Immigrant Exodus, said.

One Washington think tank estimates comprehensive immigration reform would add $1.5 trillion America's economy in the next 10 years. That's an annual increase of 0.8 percentage points to the economic growth rate, currently stuck at about 2 percent.

The consensus among economists is that an immigration overhaul could increase housing demands, encourage entrepreneurship, raise tax revenues, and eventually aide in reducing the budget deficit.

The bottom line is a net benefit. Although there is little agreement on the size of the impact on economic growth.